Continue collaborative research with investigators in Latin America. Continue pathological studies of premalignant lesions in New Orleans autopsy and surgical pathology specimens, and to correlate findings with incidence and pathology data from other communities. These studies will focus on premalignant lesions in the large bowel, esophagus, and pancreas. Continue laboratory studies aimed at finding ways to elaborate and test hypotheses derived from studies of epidemiology and geographic pathology. This will include a comparative study of the mutagenic activity in fecal specimens from polyp-bearers and controls.